When Shinzo Abe dissolved the Lower House last month for the Oct. 22 snap election, doubts were cast over the prime minister's so-called prerogative to dissolve the Diet's lower chamber, which has long been taken for granted in Nagatacho. Critics and opposition parties charged that Abe was abusing his power to his and his Liberal Democratic Party's greatest advantage — to call a snap election while his opponents were still unprepared and to forestall further Diet grilling of his administration over scandals that had damaged its popular support. The government insists that the Constitution does not impose any restrictions on the Cabinet — and the prime minister as its head — dissolving the Lower House, and that the decision on when to do so rests with the Cabinet at its political responsibility. But if there is room for abuse, discussions are needed on whether that power should be restricted in some ways.

Prime ministers have dissolved the Lower House at their will to call snap elections at the time of their choice. It enables them to hold elections at the best possible timing for their own party. But since doing so deprives the elected members of the Lower House of their status midway through their four-year terms, it has been deemed that the prime minister needs a justifiable cause. Abe said he was seeking a fresh voter mandate for his plan to divert the use of revenue from the next consumption tax hike and for him to address the security threat from North Korea on a solid political footing. Given the solid majority that his ruling coalition commanded in the Diet, that sounded like a lame excuse against the criticism that he was using the power for his partisan interests.

In fact, the Constitution does not have any provision explicitly giving the prime minister "exclusive" power to freely dissolve the Lower House. Article 7 lists "dissolution of the House of Representatives" among the "acts in matters of state" that the Emperor shall perform on behalf of the people "with the advice and approval of the Cabinet." Article 69 says, "If the House of Representatives passes a non-confidence resolution, or rejects a confidence resolution, the Cabinet shall resign en masse, unless the House of Representative is dissolved within 10 days."